Intel® PXA26x Processor Family Developer’s Manual 16-1
Network/Audio Synchronous Serial Protocol Serial Ports 16
This chapter describes the signal definitions and op eration of the In tel® PXA 26x Pr ocessor Fa mily
Network and Audio Synchronous Serial Protoc ol (S SP) s erial p or ts. The Netw ork S SP (N SSP) and
Audio SSP (ASSP) are similar except for the following:
External pin connections
Memory map base location
The Network ASSP supports swapping the receive and transmit data pins. See Section 4.1,
“General-Purpose Input/Output” on page4-1.
The NSSP and ASSP are configured differently than the SSPC.

16.1 Overview

The NSSP and ASSP ports are a synchronous serial interface that connect to a variety of external
analog-to-digital (A/D) converters, audio and te lecommunication CODECs, and many other
devices that use serial protocols for data transfer. The SSP ports provide support for the following
protocols:
Texas Instruments (TI) Synchronous Ser ial Protocol*
Motorola Serial Peripheral Interface* (SPI) protocol
National Semiconductor Microwire*
Programmable Serial Protocol (PSP)
The NSSP and ASSP ports operate as full-duplex devices for the TI Synchronous Serial Protocol*,
SPI*, and PSP protoco ls and as half-duplex de vices for the Microwir e* protocol.
The FIFOs can be loaded or emptied by the CPU using programmed I/O or DMA burst transfers.

16.2 Features

Supports the TI Synchronous Serial Protocol*, the Motor ola SPI* protocol, National
Semiconductor Microwire*, and a Programmable Serial Protocol (PSP)
Two independent transmit and receive FIFOs, each 16 sam ples deep by 32-bits wide
Sample sizes from four to 32-bits
Maximum bit rate of 13Mbps in slave of clock mode, requires using DMA
Master-mode and slave-mode operation
Receive-without-transmit operation